How this calculator works
The calculator uses room perimeter minus skipped openings for net crown molding length. It applies the waste allowance to estimate order length and divides by stock board length for board count. Corner cuts include four inside corners for a simple room plus outside corners entered by the user.
Example: an 18 ft by 12 ft room has a 60 ft perimeter. With 12% waste, order length is 67.2 ft, which rounds to 6 boards at 12 ft each. Four inside corners plus two outside corners gives 6 corner cuts.